Carrie Underwood may have already picked out her summer wedding venue and confirmed catering options, but there's one big hurdle that remains an unknown: Her honeymoon!

"[Planning] that was Mike's project," Underwood, 27, told reporters at the CMA Fest at Nashville's LP Field Thursday of her fiance Mike Fisher. "It's a surprise. I have no clue where we are going, which is nice. I know it will be warm, that's about it."

"Both of us are really busy. I still have a tour to finish," the singer explains. "There are a lot of great things going on this summer so [we're] getting through all that and taking things one step at a time and [having] lots of phone and email conversations."

"We really didn't register because we just want people there [at the ceremony]. The basics are always nice — a nice wine or something. You can write your name on it so when you come over for dinner, we break it out. We just want people there, that's the best gift."